Biology

The correct answer is: A.They send chemical signals between nerve cells or neurons.

Explanation:

In the nervous system, neurotransmitters are chemicals that transmit signals between neurons (nerve cells) or between neurons and other types of cells (such as muscle cells). When an electrical signal (action potential) reaches the end of a neuron, neurotransmitters are released into the synapse (the gap between neurons). These chemicals bind to receptors on the next cell, allowing the signal to be passed along.

The other options are incorrect because:

B.They transmit electrical signals through blood vessels: Electrical signals are ...